🔗 Share this article Ancient Hominins and Early Humans May Have Kissing, Researchers Suggest Among seabirds to polar bears, chimpanzees to orangutans, certain species appear to kiss. Currently, researchers suggest that Neanderthals did it too – and might even have locked lips with early Homo sapiens. Shared Oral Evidence This isn't the initial instance scientists have proposed ancient relatives and Homo sapiens were closely connected. In previous studies, scientists have found humans and their Neanderthal relatives shared the same mouth microbe for millions of years after the evolutionary divergence, suggesting they swapped saliva. "Likely they were engaging in intimate contact," she said, adding that the idea chimed with research that has revealed people of certain genetic backgrounds have bits of Neanderthal DNA in their genome, demonstrating genetic mixing was occurring. Romantic Interpretation "This offers a more romantic spin on human-Neanderthal relations," Brindle commented. Writing in the publication Evolution and Human Behavior, the researcher and colleagues detail how, to investigate the evolutionary origins of kissing, they first had to develop a definition that was not restricted by how humans kiss. Defining Kissing "There have been some efforts to describe a intimate act, but it's largely human-centric, which means that basically non-human species don't kiss. Currently we understand that they probably do, it might just not look from what our intimate contact looks like," explained Brindle. Nonetheless, she noted some behaviors that resembled intimate contact were something rather different – such as the processing and food sharing, or "mouth contact", observed in aquatic species known as certain marine animals. Consequently the team developed a definition of intimate contact based on friendly interactions involving intentional oral interaction with a individual of the same species, with some motion of the oral area but absence of food. Research Approach The lead researcher explained they concentrated on accounts of kissing in non-human species from the African continent and Asian regions, including bonobos, apes and orangutans, and used online videos to verify the reports. The researchers then integrated this data with details on the genetic connections between living and extinct types of such animals. Evolutionary Timeline The team propose the results suggest intimate contact developed approximately 21.5m and 16.9 million years ago in the predecessors of the great primates. The position of Neanderthals on this evolutionary lineage suggests it is probable they, too, engaged in a kiss, the researchers say. But the activity might not have been limited to their own species. "The fact that humans engage intimately, the reality that we currently have shown that ancient relatives probably kissed, indicates that the both groups are also likely to have engage," Brindle added. Evolutionary Significance Although the evolutionary explanation is discussed, Brindle said kissing could be employed in reproductive situations to potentially enhance reproductive success or assist in selecting between partners, while it could assist reinforce bonding when practiced in a platonic way. Another expert in the behavior of primates said that as kissing behavior was seen in a broad spectrum of apes it made sense its roots extend far into our ancient history, and an examination of various types of intimate behavior among a wider variety of animals might push its origins back even earlier still. "Things that we think of as signatures of our species, like kissing, are not unique to us if we examine carefully at other animals," the expert noted. Social Elements Another professor explained that intimate contact had a social component as it was not common to all societies. "However, as humans we thrive or fail on the strength of our emotional bonds, and methods of promoting trust and intimacy will have been significant for eons," she said. "It might be an concept that appears a bit contradictory to our misplaced ideas of a supposedly aggressive and aggressive past, but really it ought to be no surprise that ancient hominins – and including Neanderthals and our human ancestors collectively – engaged intimately."